In the past various types of plastic screw closing mechanism having multiple sealing threads have been proposed and produced. Some types of screw caps proposed have deformable depending skirts of flanges. For the most part past prior art caps have not only involved complicated and expensive mold forms but also required the use of a substantial amount of plastic material in order to effect the desired sealing fit.
In many instances, the configuration of the cap did not insure the preservation of the seals and thereby did not provide leak proof qualities.
Accordingly, there is a need for simple, easily manufactured, inexpensive, but durable blow molded container which has leak proof closure facilities.